Pump and valve structure



MarCh 16, 1954 R, A SHlELDS 2,672,101

PUMP AND VALVE STRUCTURE Filed March 24, 1948 -,G'ai i Ma@ Patented Mar. 16, 1954 UNITED STATES ATENT OFFICE 5 Claims. (Cl. 10S-178) This invention relates to pumps in general and in particular to small pumps that may have to pump liquid and gas under fairly high pressure and operate at high'speed.

The ordinarytype of reciprocating pump can not operate eiciently at high speed and pump both-gas and liquid, for the simple reason that the gas will be compressed and immediately ex-` pand on the intake stroke and prevent the piston pulling in more liquid or gas. This is particularly true` where the liquid being pumped is gasoline or other uid which will boil readily upon reduction of pressure. Small rotary pumps have been built which can handle the liquid and gas; but are extremely expensive, particularly where they must develop a relatively high exhaust pressure. Reciprocating pumps which are designed to handle small quantities `of liquid under high pressure require extremely close tolerances with the result that the price becomes prohibitive, particularly where the amount of liquid pumped varies as in an internal combustion engine using fuel injection.4 'It is an ob-f ject, therefore, ofthe present invention to provide a constant displacement reciprocating pump which can handle either vapor or liquid alone or combined.

`rA further object of the invention is the provision of a small high speedhigh pressure pump having valve structures 4immediately responsive to change in pressures so as to close the inlet and outlet ports even at high speed.

A still further object of the. invention is the provision of a small high pressure yhigh speed pump which can ,handle varying Yamounts of liquid, yet which does not require expensive machine work to construct. v A yet further object of the invention is the provision of a pump having the inlet valve and piston head formed integr v 7 These and other O bjectsof the invention will be apparent to persons skilledinl the art from a study of the following description and accompanying drawings, in which: f A Y Fig. 1 is a sectional view taken through the improved pump structure; i Fig. 2 is a sectional view similar to Fig. 1 but showing the pump on the intake stroke at lthe left hand side of the gure andon the exhaust stroke at the right hand half of the figure; and l Fig. 3 is a sectional' view similar to Fig. ibut showing a modication.

' Referring now to the drawings-'in detail, it will be seen that the pump is formed ingeneral o fa housing A; vcylinder structure .PL andpis'ton-structure. C. The housing structure A is generally cylindrical in form, having an outer wall l2, a top wall 4 and bottom wall 6. The top and bottom walls are bored to provide opening 8 for reception of the cylinder structure B. The bottom wall 5 is drilled and adapted to receive a fitting Ii) in which is soldered or otherwise secured a discharge pipe I2. The upper wall 4 has a shoulder thereof adapted to receive a bushing member I4 by means of which the cylinder and piston assembly may be clamped into the housing A.

The cylinder structure B is of cylindrical form having its central portion bored out as at I6 to form the cylinder walls' and the top part is counterbored as at I8 to permit insertion of compression spring 20, the bottom end of which rests upon the shoulder formed by the counter-v bore. The bottom 22 of the cylinder has bored therein a small passage 24 from which a plurality of -small passages 26 radiate outwardly and downwardly, thus forming the exhaust passages from the cylinder. A portionA of the bottom is bored to provide a recess in which the discharge valve 28 may be placed. This valve is' preferably made of a synthetic rubber or other resilient material having its edges only cemented tothe cylinder in an annular area outside of the area in which the passages 26 pass through the bottom wall. A small passage 30 is punched or otherwise formed in the central part of the valve structure 28. In order to provide space into which the valve structure may deecta resilient washer -32 is placed between the valve and the housing bottom and will be tightly clamped onto the bottom by means of the busheing I4 bearing on the top edge of the cylinder; Cylinder inlet ports are provided Vby boring straight through the cylinder as at 34.'

The piston structure C is formed with a head portion 36 adapted to be struck by a cam or other operating part to cause' inward motion of the piston under the power stroke. Inwardly of the operating head surface a shoulder 38 is provided which is adapted to strike the overhanging lip 46 of the bushing I4 and thereby limit the outward stroke of the piston under compression of the spring 20 which bears at its upper end upon the inner surface of the shoulder 38. 'The lower portion of the piston is machined to provide a surface 42 having fairly close engagement with the cylinder walls I6. A passager 44 is bored upwardly in the piston for the purpose of receiving a plug member 46 driven, pressed or shrunkinto" thpassage 44. lThis plug 46 is pro- Y vided with upper and lower transverse or radial passages 48 and 50 respectively joined by an axial passage 52. The lower end of the plug is machined away slightly so as to provide a clearance 54 between the plug and passage 44 in the region of the transverse passage 50. A piston inlet supply passage 56 is bored radially through the piston and in order to supply fluid to this passage the piston has a groove 5B cut therein to provide clearance between the cylinder walls and piston in the zone 'of the transverse passage 56, thus irrespective of the position of the piston in the cylinder, fluid or other matter can enter the piston from cylinder port 34. A combined inlet valve and piston end member 60 is provided and this member is preferably "made of resilient, synthetic material acexnented or otherwise secured to the annular area of the bottom end of piston structure C. The inner 4central area of this valve and piston member 60 will be `ffiiee of .connection 'to 'the 'plug .W6 :and is provided `r-in fitsrcentral 'portion with :an 'inlet :passage 62. 'The resilient'member 6l! is compressed slightly .against the `walls of cylinder .1.6 :and "will eiectively seal against any leakage of liquid :or vapor :along `the cylinder .walls 'Inzoperationzthe'pistonoperating head will Joe moved inwardly and .outwardly at a vfairly high rate of `'speedcaus'ing A.the i.piston and valve member l.6.0 toloscilla'te :between thefull .line position of Fig. 11 fand the 'full line v'position :at the .right hand side of Fig. 2. During the downwardfstroke the gas l'or liquid ben'eath the Apiston member 60 will be 'forced through the :passages 2.4 and 26 and :against the flexible member 2B. Pressure of the fluid :or vapor against vthe #member .'28 will cause'the :same =to deflect `as shown in the right hand lhalf :of Eig. .2:.and the fluid and vapor can discharge lfrom the passages :outzthrough vpassage 3-0 @in `the :valve member. cpmmexrcementloftthe backward stroke of piston structure l.C -the valve member '.28 will .seat due .to the v.natural resiliency -.of .thetmaterial and .due to the pressure iex-isting in =p`ipe 1'2. Upward movement of the pistonfwillcause.iluidsorfgas'in fhousF ing A to flow'throug-hzthe passages v.34 .inthe cylinderl 'Sinto .':clearance 438 and 'passages .56 in .the piston. `ilrom 56 theafluid orfgas willlow'through passages 648, 52 .and 1.50 :into .clearance Lspace 54.

Thisawill Acause'the'resilient piston .structure and valve fmember i60 #to deflect as .shown .in the `left hand portion Yof Fig.';2 fand the fluid :or gas can flow 'through :central .passage 62 finto 'space ibeneath the piston fend. .Since the pump is of1constant displacement, it z.will :be :understood that liquid orgas wllfbesupplied'ito the reservoir Vl't 'in housing Alby :means of an inlet-passage 611 ata varying rate, 'lthus since the 'pump .is 'supplied with liquid :at r-a varying frate, its discharge ywill be :at a varyingfrate, leven thoughfthe stroke and speed 'are fconstant. 'The Ypump vwill `handle both liquid gor -igas :or la vcombination .of '.both, since 'the clearances .':betweenrthe 'piston and .cylinder fare substantially :zero .at the .bottom end yof the .stroke andthe V`small amount pf igas w:retained in passages 2li 'and126 .is so small with respectuto the pump displacement they rcarmot expand .sufliciently to block admission nf .liquid `iur gas 'upon the'intake strokefof the pump. Furthermore, the

volume of .passage E2 .will :bedecreased :due to the flow :of :the `material `under compression thereby more nearly giving 'zero 'volume at fthe bottom of thefstroke.

.In .some cases :it `imay rbe found lconsiderably cheaper tto manufacture .the Apiston :as :shown in :immediately .upon the Aner the volume of the outlet passages is further reduced and the eiciency of the increased. 'The piston shown in Fig. 3 will have pump is slightly its upper end constructed exactly as shown in Fig. "-l but willtbe cut off immediately below the 4passage :56,

thus .leaving the plug d6 extending outwardly from the piston. In order to seal the piston Awith respect to the cylinder synthetic rubber or other resilient material l2 is vulcanized or ritherwise .adhered Lito `:tire outer @walls of 'plug t6 :and ato the inner 'walls la Joli .the .cylinder .B, thus :the 'resilient .material '.williact .in 'shear L uring the movement :of :the piston, abut being permanently locked :to 'the cylinder .and .plug 46 will positively :prevent Aany flow :of vout .of the pump v.charniber .along the Ecylinder .or 'piston surfaces. In @this zrnanner 'it :is .npt :necessary 'to carefully .watch rthe .machining .of .the parts rand the 'oost 'of :production will tbe materially 'reduced The 'resilient '.material l512 caps @the end tof the plug 45 ibut is not :adhered .Ithereto, thus 'permitting the fluid .or @gas .to fflowexa'ctly as itha't :described in :connection with Fig. .1, that ,'is,;lluid and :gas can .'enter .from clearance space :5A into ,the 4pump chamber l1 4 through the .'Openingk :formed in Lthe combined piston and :valve istructure. J'With .this structure as"in:that of Figs. ".1 and i2, the resilient materialfof '-'boththe inlet and"outlet valves will deflect to permit `entrance :or escape :or matter into ior -trom fthe pump fha'mber '.Likewise, due Ito -ithe Ausefoi `the fresilient vmateri'al, the piston can ldirectly contact Ythe 'ihottom wall -o vthe cylinder fand-thus reduce the pump displacement space or chamber "to lzero on the exhaust stroke.

While the =invention has `been-.'lescribed -more or less in detail with specific reference to the accompanying v'iigures 'it is to be understood that various modifications 'and rearrangements of parts may be "made without "departing 'from the scope 'of `'the `invention ,as defined -by the 'following claims.

What is Iclaimed is:

"1. A combinedpump :andvalve structure 'comprisinga "cylinder having Aone lend closed, a dis'- c'harge upassage vextemzling 'from the interior of the cylinder throughtheplosedsend, 'aipiston reciprocableiinthe cylinder during lintake and discharge strokes and having 'portions -o'f 'its sides spaced from the cylinder, 'an 'intake passage extending 'through the'pis'ton, ynon-'metallic resilient material 'overlapping the entire inner end 'of 'said piston -and -lling `.the -space between 7said piston portion and cylinder wall, said A"material v'being a'dhered'l-to the cylinder wall fand 'piston sides and acting in shear during r-e'c'iprocationof the piston, and 1van intake'ipassage ncontinuation extending through :said material Tin l'cffset relation to 'said first-named lIfinta'lre passage, said r'resilient ma- .teri'al 'having '-.portions thereo 'bowing 'inwardly from the inner `fendzcf 'said piston :.to admit matter through the intake and intake-continuation into .the cylinder beneath ythepiston-aand :material -during `the .intake stroke pf 'the .'piston.

.2. ,.Afcombinedmlmp and valve structure .com-

prising a cylinder having one end closed, a discharge passage extending from the interior of the cylinder through the closed end, a piston reciprocable in the cylinder during intake and discharge strokes, said piston including a plug part vpressed into the upper portion of the piston and having projecting sides spaced from the cylinder wall and also having its lower end reduced in diameten'interconnected axial and radial intake passages extending through the piston and plug part and one at least terminating at the reduced diameter end of said plug part, resilient material filling the space between said piston plug part and cylinder wall and being connected to said plug part, said material capping the end of said piston plug part and spaced from the reduced end thereof to provide annular clearance space between said resilient material and plug part connected to said intake passages, and an opening in said resilient material substantially on the axis of said piston plug part, said resilient material capping the end of said piston plug part flexing during the intake stroke to pass matter beneath the piston and material from said intake passages annular space and openings during the intake stroke of said piston.

3. The structure of claim 2 characterized in that said resilient material is connected to the cylinder wall and acts in shear during reciprocation of the piston. n

4. A combined pump and valve structure comprising a cylinder having one end closed, a piston reciprocable in the cylinder during intake and discharge strokes and having a portion of its sides spaced from the cylinder wall, an intake passage extending through the piston, non-metallic resilient material covering the end of said piston and filling the space between the sides thereof and the cylinder wall, said material being of suilicient thickness as to contact substantially the entire inner surface of the closed end of the cylinder at the end of the discharge stroke, a discharge passage extending from the interior of the cylinder through the closed end, non-metallic resilient material contacting the outer side of said closed end in an area surrounding the discharge passage, openings formed in said material out of alignment with said discharge and inlet passages, said resilient material adjacent the openings bowing away from the piston end and end wall of the cylinder to pass matter during the intake and discharge strokes respectively, and said ilrstnamed material being bonded to said piston and cylinder and acting in shear during reciprocation of the said piston.

5. The structure of claim 4 characterized in that said last-named resilient material is adhered to said cylinder closed end in an annular area surrounding said discharge passage and opening.

ROBERT A. SHIELDS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 335,271 Chase Feb. 2, 1886 1,321,923 Knox Nov. 18, 1919 2,000,883 Cullen et al May 7, 1935 2,029,367 Geyer Feb. 4, 1936 2,117,863 Szekely 1 May 17, 1938 2,457,339 Bertea Dec. 28, 1948 FOREIGN PATENTS Number Country Date 554,507 Great Britain July 7, 1943 

